Belt-type presses for making particleboard, fiber-board, and the like known in the prior art related to my invention generally comprise an endless upper press belt, preferably steel press belt, circulated over at least one upper belt guide roller, a corresponding endless lower press belt, preferably a steel press belt, circulated over at least one lower belt guide roller, these press belts forming a pressing gap in a pressing region of the belt-type press, and a press framework having a lower and an upper platen as well as a drive mechanism.
Into the pressing region between each of the platens and its corresponding press belts rods are fed with spacing from each other, and are guided over a circulation path with the aid of either or both of an upper or lower rod circulation mechanism, wherein each rod circulating mechanism comprises two first or main chains each guided over at least one sprocket and at least one first chain drive wheel, a plurality of interlocked chain, link members having chain bolts attached therein, a plurality of outer running rollers mounted on the chain bolts, and at least one guide rail for the running rollers, the rolling rods being attached between the two first chains with equalizing free play, at least one end of each of the rolling rods having a recess bored therein, in which each one of a plurality of support rods attached to the first chains engage so as to provide the equalizing free play.
At an entrance region of the pressing gap and upstream of the platens a second or bracing chain, comprising a plurality of chain rollers in a triangular configuration guided over at least one second chain guide wheel, is positioned, by the chain rollers of which the rolling rods between a respective pair of the first chains are guided as with roller bearings.
It is understood that the platens are commonly heated.
The press products can include also laminates, rubber products, plastics and the like.
In a known press of this type, as taught in German Patent documant DE-OS No. 31 19 529 (see also U.S. Pat. Nos. 4,480,978; 4,468,188, and 4,457,683), the first chain and the second chain associated with the lower press platen in the entrance region form a complete horizontal plane, while the first chain and the second chain of the upper platen are guided slantingly to the pressing gap. Of course in this way an entrance V-shaped region arises, which is not however necessarily symmetrical with respect to a horizontal central plane of the press. That has the result, that the press belt does not or at least not in every case press with adequate force on the chain rollers of the second chain.
The second chain does not belong to a mechanism for the introduction of rolling rods perpendicularly to the circulating direction, it primarily forms an individual entrance press in which the second chain in the prior art is referred to as a press belt.
For the introduction of rolling rods a particular input mechanism is provided which is equipped with connected guide strips or links cooperating with sliding wheels and with driven guide wheels, wherein in the known embodiments the first chains are pushed together or collapsed in the entrance region into a zig-zag shape and are correspondingly guided in the pressing region.
The sprockets and the second chain guide wheels are rigidly supported pivotally on the input end of the press and are not shiftable or pivotable in the horizontal direction. The rolling rods are generally unsupported during their introduction into the pressing region so that there is nothing that ensures the proper alignment. That is all right as long as the presses are not too long. However the belt-type presses in use tend to be very long so that the rolling rods are able to cant in the pressing region and in the pressing gap.